Healthy food for nursing school

I have been checking all of the boards on this site, and I have not found one post that goes into the types of food you should be eating or food that is recommended while in nursing school. I was told while I'm in my LVN program, to stay healthy, eat healthy, and to get a lot of exercise. Well I already exercise daily, its eating healthy that I'm having the problem with, lol. I weigh 104 pounds, but I feel that I really shouldn't be at that weight since I never really eat healthy anyways. I just need to start eating healthier. If anyone on here can recommend a few healthy foods that I should bring to nursing school, I would really appreciate it. What types of food should I be eating before and during school? Before studying for tests? During tests? Doing homework?